Apparatus for producing complete combustion.



J. OARTIN.

APPARATUS FOR PRODUCING COMPLETE COMBUSTION.

Witnesses.

4 SHEETSSHEET 1.

- Inventor,

John Cartm,

J. GARTIN. v APPARATUS FOR momma COMPLETE COMBUSTION APPLIUATION FILED DBO. 26, 1907.

916,996? Patented Apr. 6, 1909.

4 SHEETSSHEET 2.

IILL

Witnesses-I Inventor,

John Cartio,

Patented Apr. 6, 1909.

(L SHEETSwSHEET 3.

J. CARTINI APPARATUS FOR PRODUGING COMPLETE COMBUSTION.

APPLICATION FILED DEC. 26, 1907.

Witnesses:

J. CARTIN.

APPARATUS FOR PRODUCING COMPLETE COMBUSTION.

Patented Apr. 6, 1909.

4 SHEETS-SJIEET 4.

APPLICATION FILED DEC. 26, 1907.

UNrrnn STAT ATENT FFICE- JOHN OARTIN, OF OGDENSBURG, NEW YORK, ASSIGNOR OF ONE-TENTH TO J. WILLIAM EMOND, ONE-TENTH TO WILLIAM EMOND, ONE-TENTH TO JOSEPH EMOND, AND ONE TENTH TO WILLIAM P. KAUFMANN, OF CARDINAL, CANADA, ONE-TENTH TO ANTHONY WHITE AND ONE-TENTH TO PHILIP J. CARTIN, OF WATERTOWN, NEW YORK, AND ONE-TENTH TO THOMAS J. HALL, ONE-TENTH TO FRANK P. CARTIN, AND ONE-TENTH. TO JOHN H. CARTIN, OF OGDENSBURG, NEW YORK.

AIPIARATUS FOR PRODUCING COMPLETE COMBUSTION.

Specification of Letters Patent.

Patented April 6, 1909;

Application filed December 26, 1907. Serial No. 408,136.

-of the United States, residing at Ogdensburg, in the county of St. Lawrence and State of New York, have invented certain new and useful Improvements in Apparatus for Producing Complete Combustion, of which the following is a specification.

This invention relates to improvements in apparatus for producing complete combustion of fuel, designed for use in connection with steam boilers and the like, and the in vention relates particularly to an apparatus or furnace to be employed for producing the complete or perfect combustion of bituminous or soft coal, wood or other suitable fuel, which is largely used for making steam and for heating purposes generally.

Heretofore many attempts have been made to devise furnaces, to be operated in connection with steam boilers and other heating apparatus, for effecting the complete combustion of the fuels employed, particularly the more common variety known-as bituminous or soft coal, but so far as I am aware, none of these havebeen entirely successful. Bituminous coal, differs from the anthracite or glance coal of commerce, in that when heated, it yields a considerable amount of volatile and bituminous matter, the latter called mineral pitch, a black tarry substance, which burns with a bright flame, but when heated to a point below the temperature of ignition of its decomposition products, invariably gives off a black or yellowish-black smoke, which is heavily charged with fine particles of carbon called soot, and other matters of hydro-carbon nature. The presence of the black smoke in the atmosphere in the vicinity of heating and other furnaces is held to indicate that the fuel has not been perfectly combusted or burned. It is commonly believed that the soft or bituminous coal burned in most of the .furnaces, under the. methods heretofore employed, has not yielded the full measure or enefit of its energy, in the way of making steam,'or producing heat for other pur osos, which it is capable of producing, chie y because complete combustion of the said fuel has not been effected within the furnaces.

It is an object of the present invention to provide an apparatus or furnace, in connection with a steam boiler or other heatmg parts, in which bituminous or soft coal, wood,

or other suitable fuel may be burned, and wherein practically all of the volatile hydrocarbon matter, as Wellas the gases and other combustible properties yielded or given off by the fuel, during the differentstages of the heating and burning thereof, will be efficientlyconsumed, in the fire-boxes and in a combustion-chamber of peculiar and novel construction and arrangement, before the still combustible reek is allowed to pass away from the boiler, and wherein the entire heat'energy of said fuel may be obtained and utilized for making steam, or for other forms of heating, before.v it is allowed to escape or become wasted.

A further object of the invention is to provide an apparatus of the class, which is simple, compact, durable an'dinexpensive, and

wherein the construction and arrangement of the several parts of thefu-rnace, and the disposition and relation of the boiler are such that a greater amount of heat may be produced and then employed for making steam or for other purposes, from the same or a less amount of fuel, than is capable of being produced byany other furnace or system of the class known to me. 7 A

The invention consists principally in pro- "viding a boiler for use in making steam, or

heating Water, and suspending the same by means of independent supports within a walled inclosure or casing having anopen top. The boiler being disposed in the said inclosure or casing in suchmanner that a compartment, or chamber of considerable depth intervenes between the und r side of the boiler and the floor of they inclosure, which comprises a large combustion-chamber of substantially the same width and length as the boiler.

The invention further consists in providing two fire-boxes or furnaces and disposing them in the compartment or chamber directly beneath the opposite ends of the boiler, which are intended to be fired at the same time, or may be fired alternately, for

I the purpose of producing an intense heat,

- description.which follows,

which the inner ing them in different parts or furnace, in a manner which will their belng manipulated from the disposing the samein the combustion-chamber centrally'bene ath the boiler and between the twofire-boxes, over which the heat currents from one fire may be compelled to flow on their way tothe other end of the chamher, and which, from the nature of its material, and its arrangement and proximity to absorbing and then reflecting and radiating an intense and steady heat upwardly against the mesial portion of the boiler.

The invention further consists in provid ing means for regulating and shifting the drafts to and-from the two fire-boxes and fires in such man'nenthat the smoke and hot gases of one fire may he drawn or forced lengthwise under the boiler from oneend to the other, and directed over the said brid e and over, or under and upward through the second fire, in order to complete the combustion begun in the first fire.

The invention further consists in providing means for compelling the products of combustion from the combustion-chamber and both of said fires to pass through the flues of the boiler in diiierent directions alternately, and thence into independent smoke-boxes or like parts disposed above the opposite ends of the boiler, which connect with a common chimney.

A further feature of the invention consists in providin a combustion-chamber, in

lining and all of the fittings comprise a refractory material or substance which is capable of absorbing and retaining heat of an extremely high degree without fusing. And the invention further consists in providing a series ofnovel and simple dampers or heat deflecting parts, and disposof the apparatus permit of outside of the casing or inclosure, for the purpose of regulating and changing the direction of the flow or movement of the currents of products of combustion in different directions, both within the combustion-chamber and through the boiler.

Other features and parts of the invention will be readily understood from the detail and by reference to the accompanyingdrawings, forming a part of this specification, and in which Figure l is a plan view ofthe complete apparatusl Fig. 2 is a front end elevation. Fig. 3 is a vertical cross sectional view, substantially on the line 3 -3 of Fig. 1. Fig. 4 is a central longitudinal section,- substantially on the line 4'4 of Fig. 1. Fig. 5 is a' to and interlinked with the Similar characters of reference are assigned to corresponding parts throughoutthe several views.

In the drawings, 2. represents a steam boiler, which for the purpose of illustrating my invention, is preferably. a plain cylinder adapted for use as a. horizontal type of boiler, and having a number of fines or tubes 3, applied and-arranged in the ordinary way. Instead of mounting the boiler upon a foundation or supporting base, such as commonly employed," I prefer to suspend the boiler in a manner tirely free from supports of any kind, and for this purpose,-I provide a pair of saddles 4, which are securely riveted or bolted to'the upper side of the'boiler; each saddle having a pair of loops or eyes 5 extending upwardly,

one disposed on each side of the center of the boiler,

.6 represents a pair of loo s or eyes similar oops 5, but each having a threadedstenr to receive a nut 6 employed for attaching the loops to supporting beams 7, which are preferably the wellknown channel-beams, and these are disposed at right-angles to' and directly above the boiler, as shown. v

8 represents a series of piers or buttresses which may consist of any suitable material, as brick, of sufficient strength to support the heavy -boiler. Four of the piers 8 are shown, one dis osed beneath each end of the beams 7, the latter preferably resting upon a suitable I'netal cap or plate 8 mounted on top of the piers.

p 9 represents a steam conducting-pi e connected centrally to the top of the boiler, for carrying steam to different parts of a plant. 10 represents a safety pu pet or blow-off valve, connected to pipe 9, directly over the boiler. I i p The surface of the upper half of the boiler is preferably covered with a layer of firebrick 11, laid next to the iron, and over this covering is then spread a coatingof asbestos or like substance 12, to prevent the esca e of the heat, or the chilling of'the boiler oy contact with the atmosphere.

13 represents a walled inclosure or casing, preferably rectangular in shape, which rests upon the floor or ground, and corn letely surrounds the boiler in its Suspender posi-' tion, as described. lhis inclosure is preferably open at its top, and is formed so that the side walls substantially meet the sides of to leave its under side ena the boiler, while the end walls are disposed boiler and said walls. In height, the'walls of the casing 13' preferably extend a foot or more above thetop of the boiler, as shown in Figs. 2, 3 and 4, and the ends of the beams 7 pass through the opposite side walls to reach the piers 8 which are disposed outside said walls. At one end of the casing 13 a large square 0 ening 16is provided, to afford access to t e interior, particularly for the purpose of cleaning or blowing out and repairing the fiues of the boiler. This opening is closed by a pair of doors having metallic;

underside of the grates 23, in suitable volframes 17 which are preferably protected or shielded from the heat within the inclosure by a lining of fire-brick or like refractory substance 18. wall 13 at 19, and are provided with suitable handles and latches or other fastening means. 20 represents a circular manhole or opening formed in the opposite end of the casing 13. This opening is fitted with a circular cap or part 21, which preferably consists of 'an outer metal part lined on its hollow inner side with fire-brick, the same as doors 1'7. Y a

' In order to carry out the object of my invention, and effect the complete combustion of the fuel employed for heating the boiler, I dispose the boiler in the walled inclosure 13 in such manner, that the underside of the boiler is preferably thirty to forty inches above the floor or bottom, and by this means provide a large chamber or furnace, which I side dimensions of the inclosure, the lower as a plan area substantially equal to the inhalf of the boiler forming the upper side of the said chamber. In this space or chamber, I dispose two fire-boxes or furnaces A and B, preferably located beneath and at or near the opposite ends of the boiler. These furnaces are preferably constructed and arranged exactly alike, each having a grate .23, which ma be of any of the Wellknown patterns,

an each grate is mounted between a air'ofparallel walls or piers-24 and 25, which are' preferably made of fire-brick. These walls or piers extend crosswise in the main cham ber, at right-angles to the boiler, The outer piers. 24 are referably plain and solid and extend to wit in'about one foot of the boiler, as shown. The piers, 25 are each provided in their lower central portions with an arch 26, extending from a point near the grate to the floor, while their upper edges are formed into inverted arches .27, disposed centrally beneath the bottom of the boiler. The opposite ends of piers 25 extend upwardly to close the angle between the sides of the boiler and the walls 13, as show-n in Fig. 3.

22 represents the combustion chamber proper, which comprises the space between the piers 25, from each end of which com- These doors are hinged to the munication may be had with the fire-boxes A and B, through the respective archways 26 and 27. Beneath the grates 23 are disposed ash-pits or chambers. 28 and 28, which have direct communication with the combustion chamber 22 through the arches 26. Fireboxes A and B are each provided with a door 30, foruse in supplying coal to the fires, and the ash-pits are each provided with doors 31 for removing the ashes. The doors 30 and 31 are disposed on the front side of the casing instead of at the ends, and may be constructed and operated in any suitable manner. The'doors 31 are preferably provided with check-drafts 31 for supplying fresh air to the nine to effect the proper burning of the fuel 32, which covers the grates in the two furnaces.

33 represents a bridge, heat distributer,

and heat reflector, disposed centrally acrosswhere they may be supported in any suitable manner, then meeting in the middle of chamber 22, where theinner ends rest upon a firebrick pier 35. The bars 34 are preferably spaced about one inch apart, so as to prevent the serrated surface of the bridge from becoming covered or laden with dead or nonheat-absorbing substances, such as ashes and cinders, the sharp sloping upper surfaces of the bars serving the purpose of increasing the'heating surface of the bridge as well as rendering the same self-cleaning. Bridge 33, in practice will extend each way from the centerv of chamber 22 to within about one foot of the piers 25 which form the inner limits-of fire-boxes A and B, The object of the bridge is to providea broad surface or field of the refractory bars, which is capable.

of absorbing and retaining heat, which it receives alternately from the fires A and B, and then to reflect or radiate the said heat upwardly against the' under portion of the boiler. Bridge 33 is disposed within about one foot of the under surface of the boiler, and in such manner that the products of coinbustion produced by the fire last stoked may be directed over-the top of the bridge and made to mingle with the products of (.0111- bustion of the other-fire, at the will of the fireman. In order to compel the currents of hot air to pass through the narrow space be tween the boiler and the bridge, I provide a pair of rocking or wcillating dampers 36 and 37, preferably made of fire-clay so as to stand are fitted hand-wheels 39 and 40 (shown in v the intense heat and mounted upon tubular Figs. 1, '2, 3 and 5). The dampers 36 and 37 are both preferably operated at the same time, by means of sprocket-wheels 41 and 42, which are connected by means of a chain 43.

As illustrated in Fig. 4, dampers'36 and 37 are so positioned, that either one may be shifted or set to close the passage through the inverted arch 27, and at the same time to open the passage-or space between the ends of the bridge and the piers 25, and thereby deflect or compel the currents of hot gases after traversing bridge 33,, to pass downwardly and through the arches 26 in piers .into the ash-chambers, from whence they will be drawn upwardly through the grates and through the fires A. or B, as the case may be. In Flg. 4, the damper 36 is shown in full lines disposed vertically, thus closing the archway .27 leading directly from the bridge to fire A, and damper 37 is shown disposed horizontally, so as to close the passage leading downwardly between the bridge and wall 25 of fire-box B. Under this arrangement of the dampers 36 and 37, all of the products of combustion givenv off from fireB, must pass to the right between bridge 33 and the boiler, thence downwardly through arch 26 into ash-rpit-28, thence upwardly through grate 23 and'fire A, where it is intended that all of the uncombusted particles of the fuel of fire B will yultimately be consumed by the fire A,

an appropriate regulation of fresh air draft being arranged for through dampers 31 under furnace A. From the latter fire, the products of combustion will pass directly into the space or fiue '14, and then through the flues of the boiler, as will be more fully explained below. The fire A, as illustrated in ig. 4, represents what is calledby engineers a white fire, from which black smoke or soot is no longer.. given off. while fire B, is shown to have been freshly coaled or stoked, and represents what is termed'a-green fire, which is in condition to yield a heavy black or yellowish-black smoke and considerable gas, which in order to carry out the purpose 'IlOWBd to pass directly into the smoke space 15 and through the boiler, but must first be directed, as indicated by the arrows, in said.

I Fig. 4 along the underside of the boiler,

across the highly heated bridge, thence downwardly into ash-pit 28, and so on as last 1 described;

' In rder to regulate the flow of the products of combustion after they .leave either .of the fires, as described, and to direct them in either direction through the flues of the boiler, a pair of rotatable dampers 46 and 47 are disposed or flue chamber 14, an airof similar in the space,

dampers 48 and 49 are disposed in 'the same manner in the space or flue chamber 15,-at theopposite end of the'boiler (see Fig. 4). I Each of these dampers are preferably comprisedof sections of fire-clay 44 (see Figs. 3 and;-7-)mounted u 011' square hollow shafts 50, -throu' hj whic air may circulate to pnevent over eating ofthe-said arts. These several dampers are preferabl ormed to'substantially' the length and widt of the flues '14 and 15,'as shown.. The endsof the hollow shafts-50 tpass through the opposite sidewalls 13 o the casing, and have bearings in round bushings 51, to

permit-"them to be rotated to shift the 'dampers to different positions. I V

endsof shafts 50 which project through the on" the front wall 13, are mounted sprocket-wheels 52, which are 0 eratively connected at each end of the boi er by as rocket=chain 53.

The lower dampers 47 an 49, at the 'opposite'ends of the casing are fitted with handwheels 54 and 55 respectively, by means of which, and. by the cooperation of the sprocket gearing, the pair of dampers .at

each end of the boiler may be operated inunison. -When connect-ing'up the sprocket chains, the dampers of each set or air are disposed at right-angles, to each .ot er-and thereafter maintained in such relation, so that when the hand-wheels are rotateda' quarter of a turn, one damper will be ripened, and the other will be closed. (see igs. 3 and 4). Therefore, to permit the products of combustion to'reach the boiler flues from the fire A, as last described, the hand-wheel 54 had been operated a quarter turn, which opened the lower damper. 47, and at the same time closed the upper damper 46. The closing of damper'46, c leading upwardly from space '14 into a smoke-box or like'part 56, disposed directly above said space, and which communicates with a chimney 60, by means of. an integral neck or throat 58 and a tubular smoke-pipe 59, the latter enteringthe chimney a short distance above and rearwardly of the center osed the passage of the boiler. The shifting of the dampers 46 and 47 ,as described, compels the products of combustion then to enter and pass through the fines 3 of the boiler, from right to left, as indicated by the arrows, after which they emerge into the op osite flue 15, in which the dampers 48 and 49'a're disposed. The dampers '48 and 49 are constructed, applied and operated in exactly the same manner as the dampers at'the other end of the boiler, but in order to conduct the roducts of combustion to the atmosphere, t ese last named dampers had been set,- by manipulating the hand-wheel 55, in such manner as to close the lower damper 49 and open the uplper damper'48 (as shown inFigs. 3' and 4). T e products of combustion are then compelled to flow upwardly, and in doing so, may pass on either side of damper 48, they next enter a smoke-box'57 (which is exactly like the box 56, and also connects with the i the lagging or covering of the boiler, where it is cut away to conform to ,the curvature of the boiler, so as to make a tight closure to prevent the escape of smoke or gases into the boiler-room.

65 represents a water-gage and related parts, such as commonly employed on steam oilers, which may be of any suitable construction, but is preferably connected to the side of the boiler, instead of the end, which is the usual practice.

As explained, the coal in fire-box A has been burning for some time, and has ad vanced to the white stage, while fire-box B, is shown to have been but recently stoked with fresh coal. I condition shown and described, all of the darn )ers and draft courses are arranged (see ig. 4) to correctly show the working of my improved apparatus, and all of these parts should be left in theposition as thus shown, until ene 'of theffires requires restoking. After fire B has burned for a certain time, it will become white, and by that time fire A will have burned out to such extent that it will require a fresh supply of coal. Before the fireman begins the stoking of fire A, he should first change all of the dampers, so that when the new 'coal is thrown on the fire, the black smoke and other matter which may be given 05 from that fire may be carried across the combustion-chamber 22 and through fire B, before it is allowed to reach and pass through the boiler. In order to make ready for the next stoking of fire A, the fireman should first operate hand-wheel 55, which shifts dampers 49 and 48, opening the former and closing the latter; then he should operate hand-wheel 54 to shift dampers 46 and 47, closing damper 47 and opening damper 46. After this has been done, he should next operate either one of the handwheels 39 or 40, whichever one happens to be nearestto him, in the direction to change damper 36 from its vertical-to the horizontal position, and at the same time by the same operation, change damper 37 from the horizontal to the vertical position. The latter dampers may be changed from one position tothe other by simply rocking the shafts back and forth. The upper dampers may be With the two fires in theshifted from one position to the other by rotating the shafts in thesame direction each time. The shifting of the several dampers as-just described, will set them all in the positions indicated by dotted lines in Fig. 4. The fireman may then add fresh coal to fire A. As soon as the new coal strikes that fire, all of the smoke and gases thrown off will then be carried by the draft received through the grates of fire A toward the left, passing through'upp'er archway 27 and. across the bridge thence downwardly, through ash-pit 28, thenceupwardly through fire B, thence into chamber 15 and through the'boiler lines into flue 14, thence upwardly into smokebox 56, and from the latter into the chimney, After fire A has been stoked, all of the dampers should be left in the position last described, until. fire A has burned white", and by thattime fire B'will have burned out sufiiciently to require a fresh supply of coal. The fireman will then reshift all of the dampers back to the positions shown in full lines Fig. 4, and recoal fire B, and so on, changing all of the dampers each time either of the fires are fired anew.

By providing a combustion-chamber 'of considerable length, and disposing a fire-box or furnaceat each end with the bridge arranged between them, the roducts of com bustion from the "gr'een re at one end, in

passin to the other end of the chamber I towar and over or through the white fire-will have a tendency'to increase, rather than diminish in degree, because the 'portions of the fuel from the f green fire, such as soot and combustible gases, whichare not completely consumed within the fire-pot, or in'the superheated space directly above it, will, after the fireshave burned for a short time, continue burning during their passage over the intensely heated bridge, and along the hot inner walls of the chamber, and finally, Whatever remains unconsumed from the first fire, will become perfectly combusted while passing through the second fire and through the hot air chamber at the end of the boiler.

The entire combustion-chamber being lined with fire-brick, the fire-boxes, the bridge and also the dampers being constructed of the same material, all of which are capable of absorbing and retaining heat to a greater extent than any other form of brick or composition available for the purpose, it is possible to produce a temperature sufficiently highyto effect the complete combustion of the bituminous coal, wood, or other suitable fuel, and also to prevent black or offensive smoke from escaping from'the furnaces, after the first fire has advanced to the white state. After the fires have been burning for a short time, the whole interior of the inclosure beneath and at the ends of the boiler, will become white with the boiler, the. heating surface of which, in

any case, is little, if any hotter than that of the steam within it, which is said to be less than 350 F., for a pressureof 100'lbs. per square inch. Since the temperature of the boiler is normally low, as compared with the temperature necessary for the most'efiicient combustion, I have found that by constructing and arran'ging'the furnaces, combustion-' chamber and other related parts, in the manner as shown and described herein, will not only counteract the resistance to heat offered by the boiler, but will also render it impossible for the boiler, having a lower temperature than the furnaces beneath it, to draw the heat'from the burning gases, before the combustion of the latter is completed. After the two fires are gotten under full headway andv the furnaces and whole plant become heated, owing to the peculiar construction and arrangement of the interior of the apparatus, as described, there is little -or no danger ofeither the boiler or the central chamber 22 becoming chilled each time the fire-box doors are opened for the adding of fresh coal. a l

Having thus described my invention, what I claimasnew and desire to secure by Letters Patent,.isv 1 In'an apparatus of theclass described,

the combination with a'boiler suspended in horizontal position and. having flues therein, of a fire brickcasing disposed around the boiler and having an open top, theends of the casing being spaced from the ends of the boiler to form flues and the space below the boiler and between the side Walls of the casing forming a combustion-chamber connected-to said flues, a smoke box mounted upon each end of said casing above the ends of the boiler and communicating with the adjacent flue, a chimney to receive the discharge from thelsmoke box, a fire-box disposed near each end of, said combustion chamber beneath the adjacent end of the boiler each firebox having a grate, an ashpit beneath each grate, a flue to connect each ashpit with said combustion chamber, a bridge comprising a heat distributer dis.- posed centrally in said combustion chamber etween said lire boxes, oscillating dampers pivotally mounted in the opposite side walls,

of said casing disposed between the ends of the bridge and said fire-boxes and serving 'to control -the'flow of the productsof combustion through the -fuel .of the fireboxes alternately, a chain vconnecting said dam- 1 pers, a hand-wheel carried by each damper adapted for operating them simultaneously, a pair of rogatable dampers disposed in the flue at eac end of the boiler'adapted to cause the products of combustion to .pass

through the flues of the boiler al'tegnatel a chant to connect each pair of rotatab e dampers, and a hand-wheel carried by one I of each pair of dampers adapted for operating the same simultaneously, substantially; as described.v i 1 2. The combination with a boiler having flues therein, of a fire-brick inclosure I in which said boiler is suspended, the said'inclosure having a width substantially the same as the diameter of the boiler and hav-k nected to each ofth'e smoke boxes andlead ing to said chimney, a'combustion chamber being formed beneath the boiler between the walls of the' inclosure and connecting with saidflues, two fire-boxes, one beneath each end of the boiler, each fire-boxhaving.

a grate, parallel piers to support each grate, arched openings being formedin the inner pier of each fire-box, the upper arch-ways for communication from the combustion chamber to the spaces above the grates, the

.lower arch-ways for communication from the combustion chamber to .the ash-pit,

there being a passage to connect each firebox with the corresponding flue, a pair of dampers in each flue disposed perpendicular to each other, each pair of dampers adapted to permit or prevent the flow of products ofcombustion from either or both of the-fires directly to said flues, said dampers also adapted to permit or prevent the flow of products of combustion from said flues directly intosaid smoke boxes, and means for operating said dampers, substantially as described. 1

3. In an apparatus of the class described,

the combination with a boiler suspended in horizontal position and having a series of boiler flues extendin through the same, of a casing surrounding t o boiler and having an open top, said boiler being spaced at its ends from the ends of the casing to form flues and having a space beneathl the same between the walls of the casing forming a combustion chamber, a smoke-boxmoi'lnted upon each end of the casing above the ends of the boiler and communicating'with the said flues, two fire-boxes beneath the boiler communicating with the said fluesand the said combustion chamber, a bridge disposed centrally in said combustion chamber, said bridge comprising a plurality of bars supported at their ends by the walls of said casing, an oscillating dam,- per disposed at each end-of the bridge adapted to permit orprevent the flow of roducts of combustion from, either fire to the combustion chamber, the said dampers being operitble to compel the products'of combustion from either of the two fire boxes'to pass over.

the bridge, thence beneath and thence upwardly t rough-the opposite tire box, a pair of dampers disposed one above the other in 1 to permit and prevent the fiow of products of each of said lines, each pair of dampers operable simultaneously to open the lower end and to close the upper end of the flue and yiee versa, the said dampers adapted to be operated to compel the combined products of combustion irom the fire boxes to pass through the flues of the boiler in opposite directions alternately, each pair of dampers normally disposed perpendicularly to each other, and means for operating each pair of dampers, substantially as described.

4. In an apparatus of the class described,

the combination of atubular boiler and a 3 firebrick in'elosure surrounding the same, the said inclosure having an open top and a hollow compartment beneath the boiler, a smoke chamber being formed opposite each end of the boilerand connected with said hollow compartment, a fire-box beneath each end oi the boiler, each tire box comprising a grate and aplurality of walls and connect-ed with the corresponding smoke chamber, an upper and a lower arch-way being formed in the inner wall of each fire-box, the central portioncomprising a chamber, thesai'd hollow compartment being formed between said lire boxes and connecting with each the box by way of said arch-ways, -a bridge disposed in said chamber in a manner to provide a free passage for 'n'oduets of combustion from the top of the ridge to the lower arch of each fire box, a rock damper disposed in each of said tree passages adapted to control the flow of products of combustion to and from each lire-box, and to and from the said arch ways, the said dampers being pivotally mounted in the opposite side walls of said inclosure and capable of being operated simultaneously lvl setting the dampers in different positions, the said dampers being normally disposed perpendicularly to each other, and a hand-wheel carried by one damper lor shifting both dampers, substantially as described.

5. In an apparatus of the class described, the combination with a tubular boiler and a tour wall casing surrounding the same, the said casing having an open top and a hollow compartment hen *ath the boiler and spaced from the ends of the boiler to form flues, a lire-box disposed in each end of said hollow compartment beneath the ends of the boiler, each of said fireboxes connecting with the corresponding flue and comprising a pair of parallel piers, the inner pier of each fire box having an upper and a lower arch way, that portion of said hollow compartment between the said inner piers of the lire-boxes constituting a chamber, said chamber communicating with each lire-box and with each flue by way of said arch ways, a bridge disposed in said chamber, the opposite sides thereof being spaced equally from said inner piers oi the lire-boxes, a rocking damper disposed in the space at each side of said bridge adapted to form titles, the space between the side combustion to and from said fire-boxes through said upper arch ways and also to prevent or permit the flow of products of combustion from the upper side of said bridge to said tire boxes through said lower arch-ways, and means for operating said dampers simultaneously to set them in different positions, substantially as described.

6. In an apparatus of the class described, the combination with a boiler suspended in-a horizontal position and a casing surrounding the same, the said casing having an open top and being spaced from the ends of the casing walls of the casing beneath the boiler forming a hollow compartment, a fire box disposed near each end of said hollow compartment and communicating with said compartment and the adj acent flue, each fire-box comprising a pair'of parallel piers, one of said piers having an u per and a lower arch way formed therein a j acent' to said hollow compartment, the'said compartment com municating with each fire-box and with, the adjacent flue by means of said arch Ways, and, means Within said compartment to cause the roducts of combustion to ass from one 're-box through one upper are way and thence through the opposite lower arch-way through the other fire-box, substantially as described.-

7 The combination of a boiler suspended horizontally and having flues therein, a casing surrounding said boiler and bein spaced 10o therefrom at its ends to form flues, the space between the side walls of the casing below the boiler forming a combustion chamber, a pair of dampers journaled for rotation in each of said flues, said dampers being normally at right angles to each other,'means to operate each pair of dampers simultaneously to control the flow of products of combustion through the boiler fiues, a fire-box beneath each end of the boiler, each fire-box comprising a pair of partitions and a grate, one of the artitions being formed with an upper and a ower arch-way, a bridge located centrally in said chamber beneath the boiler, said bridge comprising a plurality of spaced refractory bars, and means within said chamber to control'the passage of products of combustion from one the box to the other by way of either of said arch-ways, substantially as described.

8. An apparatus of the class described, comprising a tu bular boiler suspended horizontally, a casing guarding said boiler and having its end walls spaced therefrom to form a lurality of fines, and said casing and boiler orming a combustion chamber beneath the boiler, a smoke box above each end of the boiler communicating with the adjacent flue, a fire-box adjacent each end of the combustion chamber, each fire box scram?1 to connect c 'onibustion, chamber with t e flue at one end of the boiler, apair of dampers in the combustion chamber adapted to direct the products of combustion from one fire-box through said chamber into a second fire-box, a pair of dampers within the flue adjacent the second fire-box ada ted to direct the products of combustion rom' both of said firesthrr'augh the boiler fiues in one direction, and a pair of dampers within the other flue adjacentthe first mentioned fire-box adapted to direct the products of combustion received from the boiler into one of said smoke boxes.

9. In a device of the character set forth,

the combination with a casing and a horiv zontal tubular boiler suspendedtherein, of a fire-box beneath each end of the boiler and spaced therefrom, each fire-boxcomprising a grate and supporting means therefor, a

bridge beneath the boiler and spaced from the supportingmeans for'the fire boxes, said bridge comprising a plurality of'spaoed horizontal bars, means comprising a pair of dampers guarding the space between the 25' means to direct the products of combustion 30' from the latter fire box through the boiler fiues' from which the are discharged at the end adjacent to the irst mentioned fire-box.

In testimony whereof I aflix my signature in presence of'two witnesses. v

JOHN QARTIN. Witnesses:

JOHN M. BARR, JorrN MTMORL Y. 

